With the increasing number and variety of Internet-of-Things (IoT) computing devices, such as home entertainment systems, smart appliances, and so forth, a growing number of services are being provided through applications (e.g., apps) that are designed to execute on such computing devices. Such applications may allow users to view information, access account data, communicate with other users, play games, make travel arrangements, shop online, consume audio, image, or video content, share content with others, and so forth. In many instances, applications designed to execute on more traditional computing devices, such as desktop computers, may be difficult to use on IoT devices that have a limited display size or limited interface functionality. Also, given the limited interface capabilities of some IoT devices, it may be difficult for users to enter authentication credentials on such device(s). Accordingly, traditional techniques for user authentication and authorization may be difficult to implement on IoT devices.